It is the worst when our furry friends pick up fleas and then bring them into our homes. Except, it’s really not quite the worst. What’s worse? When the flea collar you buy for Fido damages your child’s brain with neurotoxins.

The Natural Resource Defense Council has filed a lawsuit against the EPA related to two chemicals found in flea collars, propoxur and tetrachlorvinphos (TCVP), that the NRDC wants the EPA to ban. Specifically, the suit “seeks to force EPA to respond to NRDC’s petitions to cancel all pet uses and manufacturer registrations of these two chemicals.”

Flea collars work by intentionally leaving pesticides on a pet’s fur. As the NRDC’s health attorney explained in a blog post, according to federal law “a pesticide cannot be sold that may cause adverse impacts to human health or the environment.” If a pesticide hurts something other than bugs (like, say, people), its supposed to be pulled from the market.

These particular two chemicals can be very harmful when children ingest them, the NRDC says, likening the effects on kids to the effects of lead poisoning. The advocacy group has been petitioning the EPA to discontinue allowing the use of one chemical since 2007 and the other since 2009. In 2010, the EPA issued an assessment finding that the risks to children from toxin levels were “of concern” but the agency has not taken any further action regarding their use.

A determined young child truly will put anything and everything she can reach into her mouth. This does, in fact, include the family cat (at least until kitty learns to see trouble coming and run away faster). And while a little fur probably won’t hurt Junior, the chemicals on it can. The NRDC writes,

Once on a child’s skin, the pesticide is absorbed through the skin or it can be ingested when a child puts their hand in their mouth. Propoxur and TCVP are types of pesticides that are known to be toxic to brain development, nervous system communication and can cause cancer. Children are particularly vulnerable because their smaller bodies are still developing and their activities, such as putting their hands in their mouths after petting animals or playing, increase the likelihood and amount of these pesticides that can enter their bodies.

For consumers who want to know what brands of pet products contain which chemicals, the NRDC publishes a “green paws guide” to pet care products. The guide includes 26 products from many brands containing propoxur and TCVP.